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Ms. Lori Duncan <br /> February 22, 2000 <br /> Page 2 of 5 <br /> 2.0 BACKGROUND INFORMATION <br /> 2.1 Site Description <br /> The site is currently operated as a tire shop with a residence. The facility previously utilized two <br /> 1,000-gallon USTs for storage of gasoline and one 350-gallon UST for the storage of waste oil. <br /> The gasoline USTs were removed under permit from PHS/EHD on December 18, 1998 and the <br /> waste oil UST was removed under permit on May 11, 1999. Soil samples collected beneath the <br /> northernmost gasoline UST (Tank 2, 12/18/98) and the waste oil UST (Tank 1, 05/10/99) <br /> contained petroleum hydrocarbon constituents at levels exceeding laboratory detection limits. <br /> Analytical results are summarized in Table 1. The locations of the former USTs and collected <br /> soil samples are shown on Figure 2. <br /> 2.2 Investigations Undertaken <br /> In accordance with the approved workplan dated November 18, 1999, a total of five soil borings <br /> were advanced at the site to investigate the lateral and vertical extent of residual soil <br /> contamination. Borings SBI through S134 were advanced vertically in the vicinity of the former <br /> gasoline UST location. Boring S135 was advanced at an angle of 20° from vertical, approximately <br /> 5.3 feet southeast from the former waste oil tank. Soil boring locations are depicted on Figure 3. <br /> 3.0 INVESTIGATIVE PROCEDURES <br /> On December 8 and 9, 1999, Sean Garvey of Ground Zero supervised the subsurface <br /> investigation in the vicinity of the former USTs. Ms. Lori Duncan of San Joaquin County Public <br /> PHS/EHD conducted a site inspection and observed field activities. <br /> Fisch advanced the borings under the supervision of field geologist Sean Garvey and project <br /> manager John Lane, a California Registered Geologist, in order to explore the lateral and vertical <br /> extent of residual contamination at the site. Boring SB 1 was advanced to a depth of approximately <br /> 30.5 feet below ground surface (bgs), boring SB2 was advanced to a depth of approximately 31 <br /> feet bgs, and borings S133 and S134 were advanced to approximately 26 feet bgs. Boring S135 was <br /> advanced at a 20° angle to a depth of approximately 26 feet bgs. The borings were terminated at <br /> the depths indicated because the drillers encountered refusal of the drilling rods. Fisch utilized a <br /> truck mounted Geoprobe 5400 direct push rig to advance the borings and collect soil samples. Soil <br /> samples were collected at 5-foot intervals using a 1 3/4-inch diameter by 24-inch long core sampler. <br /> The sampler was lined with clear acetate sleeves, affording soil identification and subjective <br /> evaluation for contamination. <br /> A flame ionization detector (FID) was used to monitor the presence of volatile organic <br /> compounds in the soil. Three soil samples from each boring were sealed, labeled, and <br /> immediately placed in an iced cooler for transport to a state-certified analytical laboratory. Soil <br /> samples were selected based on observations and field screening results. <br /> The completed borings were backfilled to the ground surface with neat cement grout. No soil <br /> data\groundze\franks lire\subsurfsundoc <br />